Water tube boiler



March 15, 1938. s. L. G. KNOX 2,110,882

- WATER TUBE BOILER l Filed Jan. s, 195e 2 sheets-sheet 1 We 1% a e,

March 15, 1938.

s. L. G. KNOX 2,110,882

WATER TUBE BOILER Filed Jan. 8, 1936 2 sheets-sheet 2- Patented Mar. 15, 1938 UTED STATS Application January 8, 1936, Serial No. 58,178

20 Claims.

This invention relates to improvements in Water tube boilers and more particularly to a system for improving the circulation oi water in the boilers.

In explanation of the various aspects of invention to be disclosed hereinafter, it Will be understood that natural circulation in a water tube boiler depends on the difference in specific gravity of the water in the ascending or uptake and the descending or downtake tubes, vThe water in the tubes nearest the llame not only becomes the hottest, but also steam is generated most rapidly in those tubes, with the result that the mixture of steam bubbles with the Water makes the column of water and steam lighter and enables the weight of the water in the colder or outside tubes to force the lighter columns upward, thus creating the necessary circulation.

After the water has begun to make steam, however, there is in a boiler of the type under consideration relatively little difference in the temperature between the outer or descending column of Water and the inner or ascending column 25 of water, as the rapid circulation mixes all of the water in the boiler. The circulation under these conditions therefore depends almost entirely on the weight differential in the respective columns of Water due to the difference in quane 30 titles of steam entrained in the columns. It has been previously proposed to inject feed 'water directly into the downtake tubes and such has beneficial effects on the circulation in that the tendency of steam bubbles to form in the de- 35 scending column of water is eliminated or reduced and at the same time the descending column of water is selectively cooled whereby its weight is increased to overbalance the weight of the rising or ascending column of water.

My invention contemplates augmenting the beneficial results of injecting feed water into the descending column of water by supplying water successively or serially to limited groups ofdown- `take tubes so that a limited number of such tubes, such as one bank of downtak'e tubes, is supplied with feed water to the exclusion of other groups of banks; then a following group or bank of tubes is in turn supplied with feed water; and so on, until upon the completion of a cycle each bank of downtake tubes has received its charge of feed water in successive order. This arrangement has decided advantages as compared with letting all of the feed water mix with all of the downflowing Water at the same moment, because the concentration of all the feed water, prefer- Aiii ably in the form of jets, into a limited number of tubes results in the jets having increased mass and velocity, thus providing improved injector action and increasing the velocity of flow in the particular bank of tubes being supplied with feed water beyond that due to differences of specific gravity alone, thereby giving increased momentum and resultant persistance of the accelerated movement to the downflowing column of water. Another benecial eect of my above described arrangement is that the injection of feed water into any given tube in greater mass at a given moment than the alternative way will act to minimize any tendency to form steam bubbles.

This improved system of feed water supply is designed to give excellent circulation, but as the most rapid circulation practicable is highly desirable, because the steam output increases for a given heating surface the more rapid the circulation, and other beneficial results are also thereby attained. I may also provide means by which the circulation may be further assisted. such means being used under conditions where a greater capacity of circulation is desired than that which is afforded by the natural circulation, whether or not such natural circulation is assisted by the system of feed water injection described above. y

Accordingly, among the objects of my invention may be noted the provision of a simple yet 'highly efiicient system for supplying feed water to a water tube boiler in such manner as to give an improvement r`over the natural circulation, and/or the provision of means for further assisting the circulation if and when desired, all as more particularly described hereinafter.

Other features and their objects will be in part obvious from the annexed drawings and in part hereinafter indicated from tl'e following analysis of the invention, in which reference is made to the accompanying drawings illustrating an embodiment of my idea.

In the drawings- Fig. l is a transverse section through. a boiler of the water tube type in accordance with my invention, the connections to the feed water supply pipes being shown diagrammatically;

Fig. 2 is a longitudinal section taken along lines 2-2 of Fig. l;

Fig. 3 is a section taken along lines 3-3 of Fig. l;

Figs. 4 and 5 are detail views illustrating the arrangement of leed water supply tubes and the Fig. 6 is an enlarged 'detail in section taken through the central water drum and impeller disposed therein;

Fig. 'l is a detail in section illustrating a suggested form of connection between the outer and central water drums;

Fig. 8 is a detail view illustrating diagrammatically a preferred connection between a water supply main and the suction side of the feed water pump.

In the drawings wherein is illustrated one physical embodiment satisfying my invention, the reference characters III and II designate a pair of steam and water drums each of which is connected with a central water drum I2 by a plurality of banks of uptake tubes IL-I4, I5-I0, of which the banks of tubes I2-I4 connect the water drum I2 with the steam and water drum I0, with the banks of tubes IB-IS connecting the water drum I2 with the steam and water drum II. The drums Il and II are also connected with the central water drum I2 by banks of downtake tubes I'I-IB, IS-M, of which banks of tubes I1-I8 extend between the steam and water drum I0 and an outer water drum 2i which functions as a collecting header and which is connected to the central water drum I2 as by a series of connector tubes 22. Similarly, the steam and water drum II is connected to the central water drum I2 by the banks of tubes I`9-20 through the companion outer water drum 22 connected as by tubes 24. In addition to or in substitution for the connector tubes 22, 24, the outer drums 2|, 23 may be connected to water drum I2 by means of manifolds 44, 41 to be described, which extend transversely at one or both ends thereof. The boiler at its rear side may be provided with a screen of vertical uptake tubes 2l which extend directly between the central water drum I2 and the steam and water drums III, Il, the tubes 25 on one side of the vertical center line of the boiler delivering to the steam and water drum III and the tubes on the other side delivering to the companion drum II.

While inthe boiler illustrated I have shown a pair of steam and water drums, Awith two banks of uptake tubes and two banks of downtake tubes V extending between the water drum and each steam and water drum of the pair, it will be understood that this arrangement, while preferred, is capable of modication, and a greater or lesser number of banks of uptake and downtake tubes, and more or fewer drums, may be provided in accordance with my invention to satisfy individuai design requirements. f

Steam collectingl pipes Il, 3|l which function to collect steam from the steam and water drums Il, II, respectively, are provided, suitable connection (not shown) being made between the collecting pipes and banks of superheating tubes shown partially and designated at 22, Il, a bank of such superheating tubes being disposed preferably between the banks of uptake and downtake tubes at each side of the boiler. 'Ihe banks of superheating tubes are suitably baiiied as by baille plates 25, 30, and 31, 2l.

In order to supply feed water to the boiler in such manner as to mix with the boiler water, I

provide feed water supply pipes 40, 4I, arranged in the steam and water drum III and like feed water supply pipes 42, 42, arranged in the drum II, it being noted that one supply pipe may be provided for each bank or group of'downtalreV tubes. The said feed water supply pipes 40-4I,

42-43 extend longitudinally of the said drums III, i

II and are arranged near the mouths of downtake tubes II-I8, I9--2Ii to deliver thereto, through nipples 45, feed water supplied to the said feed water pipes. By reference to Fig. 4, the nipples 45 are joined to the feed water supply pipes in such manner that the nipples extend along the center line of the downtakertubes or the portions of the downtake tubes immediately adjacent the drums III and II with which they communicate. The nipples are further of relatively small diameter in relation to the diameter of the downtake tubes so that the feed water issues through the nipples 45 in jet form and acts not only to supply necessary feed water to the system but also functions to draw water into said tubes from the steam and water drums I0 and II with an injector action, whereby to obtain circulatory effect.

By reference to Fig. l, the downcoming water column flows to the outer water drums 2l, 23, and is thence delivered to the central water drum I2 through the previously described connector tubes 22, 24, and/or the manifolds 48, 41 and from the water drum I2 circulates upwardly through the uptake tubes I3--I4, IS-IG to the steam and water drums II) and II where steam is collected in the dry pipes 30, 3l.

In order toprovide an Aincreased path of circulation between the outer water drums 2|, 2l and the' central water drum I2, the previously referred to manifolds 46, 41 are provided and extend transversely between the outer drums 2 I, 23.

at one or both ends of the boiler and deliver to the central water drum I2.

Considering now the means for supplying feed water to the several feed water pipes 40-4I, 42-42 and thence to the downtake tubes, such may include a multiple plunger feed pump generally designated at 50 and suitably driven from a power shaft 5I. Individual connections are provided between the several pump cylinders and the several feed water supply pipes 40-4 I, 42-43 whereby, with the plungers delivering in timed sequence, each plunger delivers feed water to the aforesaid supply pipes successively and in predetermined time relation.

Referring to the feed water pump as more clearly illustrated in Figs. 2 and 3, the multiple plungers are driven from a symmetrical crank shaft l2 and operate in the pump cylinders 40a, 4Ia, 42a, 43a, each of which is connected to a 'supply main 52 (Fig. 8) through a suction line 64 suitably valved as at 55, the cylinders delivering past a back check valve 54 through pipe lines 40h, 4Ib, 42h, 42h, respectively, of which delivery line 4Ib is directly connected to the feed water supply pipe 40, line 4 Ib is directly connected to the feed water supply pipe 4I, and so on.

By the aforesaid arrangement, plunger of cylinder 40a will deliver upon its up stroke a charge of feed water through line.40b to the feed water supply pipe 40. Consequently, an increased mass of feed water at relatively high velocity is delivered through the nipples 45 associated with the feed water supply pipe 40. As plungers of cylinders 4Ia, 42a, 43a in turn act to supply water to the related feed water supply pipes 4I, 42 and with the greater mass of water delivered to the particular downflow tubes at a given moment, tending to kill the tendency to form steam bubbles in those tubes.

While the above described arrangement is designed to provide an improved or assisted circulation system, it may be under some circumstances desirable to still further, or by other means, assist the circulation, and I provide means for thus assisting circulation as aforesaid. Such preferably comprises a rotary impeller or runner 60 disposed in the central Water drum I2 and extending throughout the length thereof, the impeller interior receiving downilow water at both ends through the end connectors 46, 4T. The impeller 60 is in the nature of a hollow tube smaller than the drum l2 and is mounted on a shaft 6l f sultablyjournaled as in the end connectors 46, #il and driven in any suitable manner. By reference to Fig. 6, it will be seen that the impeller tube is suitably apertured throughout its length as at 65 whereby Water may pass from the interior of the tube outwardly int the drum i2, the apertures being of a size and in number as to distribute the flow uniformly throughout the length of the water drum l2. The impeller tube titi is provided on its outer surface with impeller blades 66 which function on rotation of the impeller to give added pressure to the water leaving the tube through apertures 65 thereof whereby to force Water into the banks l3-I4, Iii-I5 of uptake tubes.

It will be understood that rotation of the impeller 60 causes water from the outer drums 2i, 23 to bedrawn through the end connectors 46, 41 into the impeller tube and thence outwardly through the perforations 65, whereupon blades 66 act to force the water into the uptake tubes.

In order to direct circulation in its proper paths when the impeller is installed, itis desirable to plug or substantially plug the cross connector tubes 22, 2li, if such cross connector tubes are incorporated in the boiler, and such may be accomplished as by the provision of diaphragms or check Valves as shown in Fig. 7. Check valves S1 illustrated are of the poppet type, each seating against a seat formed in apertured disc 68 threaded or otherwise secured in the ends of each of the cross connector tubes 22, 24, which ends may project slightly into the outer Water drums 2l, 23. The stems 59 kof the valves are each guided in spaced guide plates l0, whereby the valves seat upon the occurrence of appreciably increased water pressure on the central water drum side of the valves, as would occur with the impeller running, thus to prevent reverse circulation due 'to impeller action. It will be understood that unless the cross connector tubes 22, 24 are plugged in the manner described, or in a manner equivalent thereto, rotation of the impeller would forcev water from the central water drum l2 into the outer Water drums 2i, 23, this being the reversal of the proper direction of iiow.

Natural circulation or circulation assisted only by the feed Water jets can take place with the impeller installed but not turning due to the provision of the apertures 65 through the impeller tubes which permit water entering the tube from the outer water drums 21,23 through cross connectors 22, 24 and/or end connectors 46, 'i1 to 'flow through holes 65 and thence into the uptake tubes. It will be understood, therefore, that when natural circulation or circulation assisted by feed water ljets only is suflicient, the impeller need not be rotated, or even not installed,

but where the impeller is installed and it is desired to assist the circulation, the cross connector tubes 22, 24 are plugged or substantially plugged in the manner described, and the impeiler is rotated through a suitable connection with a convenient power source.

Under certain conditions, it might be desirable to divide the volume of water directly available for an explosion should a crack develop in any drum. To provide for such an arrangement, I may position in all of the drums intermediate transverse partitions 75 capable of withstanding the full pressure (see Figs. 2 and 3). Such partitions divide by two the volume of water in the boiler and neither natural nor assisted circulation would be interfered with, as the intake for the latter goes from the ends of the outer water drums 2l, 23 and towards the center of the drum l2. With a partition 15 arranged in .ited to such an arrangement.

,through the partition and is journaled therein.

While in the foregoing description and accompanying drawings reference is made to drums which are shown or referred to as horizontal, and to generally vertically trending uptake and downtake tubes, the principles of jet and/or impeller assisted circulation comprising the dominant features of the present invention are not lim- On the other hand, such principles can be readily applied with beneficial results to boilers where the drums are vertically arranged with the tubes lying in horizontal or nearly horizontal planes, and to boilers where the drums and/or tubes are arranged in a position intermediate the horizontal and vertical; andall such physical arrangements to which the principles of the present invention are applicable are intended to be embraced within the scope of the appended claims.

It will further be understood that means for supplying feed water serially tothe several banks of downtake tubes other than the multi-plunger pump may be utilized in carrying out the principles of jet assisted circulation as aforesaid. For example, a single plunger or other type of pump or injector with a distributing valve revolving at a predetermined speed could be used to produce the serial distribution of feed water to the several groups or banks of downtake tubes, and all such obvious modifications are sought and intended to be covered herein.

claim:

1. In a water tube boiler, a steam and water drum, a water drum, at least one group of uptake tubes extending between said drums, a plurality of groups of downtake tubes extending between said drums, and means for` supplying successive charges of feed water to the several groups of downtake tubes. 4

2. Ina water tube boiler, a steam and water drum, a water drum, at least'one group of uptake tubes extending between said drums, a plurality of groups of downtake tubes extending between said drums, and means for supplying feed water serially tothe several groups of downtake tubes.

3. In a Water tube boiler, an upper steam and water drum, a lower water drum, a water header, connections between the header and the water drum, at least one group of uptake tubes extending between said drums, a plurality of groups of downtake tubes extending between the steam and water drum and the Water header. and means for supplying feed water serially to the several groups of downtake tubes.

4. In a water tube boiler, a plurality Qf steam and water drums, a water drum, .at least one group of uptake tubes extending between the water drum and each of said steam and water drums, a plurality of groups of downtake tubes extending between each of the steam and water drums and the water drum, and means for supplying feed water serially to the several groups of downtake tubes.

5. In a water tube boiler, a steam and water drum, outer water drums associated with said drum, a central water drum, connections between the outer and centralwater drums, at least one group of uptake tubes extending between the water drum and each of the steam and water drums, a plurality of groups of downtake tubes extending between said steam and waterand said outer drums, and means for supplying feed water serially to the several groups of downtake tubes.

6. In a water tube boiler, a plurality of steam and water drums, outer water drums associated with the steam and water drums, a central water drum, connections between the outer and central drums, at least one group of uptake tubes extending between the water drum and each of the steam and water drums, a plurality of groups of` downtake tub extending between each of said steam and water drums and its associated outer drum, and means for so injecting feed water into said downtake tubes that circulation of water in said boiler is assisted..

7. In a water tube boiler, a steam and water drum, a water drum, at least one group of uptake tubes extending between said drums, a plurality of groups of downtake tubes extending between said drums, a multiple plunger feed water pump. and connections between said pump and downtake tubes whereby the pump delivers feed water serially to the several groups of downtake tubes.

8. In a water tube boiler. a steamand water drum, a water drum, a water header, connections.

between the header and the water drum, at least one group of uptake tubes between said drums, a plurality of groups of downtake tubes extending between the steam and water drum and the header, a multiple plunger feed water pump, and

connections between said pump and the downtake tubes whereby the pump delivers feed water serlally to the several groups of downtake tubes.

9.In a water tube boiler, a plurality of steam and water dr ms, outer water drums associated with said drums, a central water drum, connec-v tions between the outer and central drums, at

least one group of uptake tubes extending be'- tween the central water drum and each of the steam and water drums, a plurality of groups of downtake tubes extending between each of said steam and water drums and its associated outer water drum, a multiple plunger feed water pump, andconnections between said pump and downtake tubes whereby the pump delivers feed water serially to the several groups of downtake tubes. l0.v In a water tube boiler, a'steam and water drum, a plurality of feed water pipes disposed therein,'a water drum. at least one group of uptake tubes extending between said drums, a group `of downtake tubesassociated with each of the feed water pipes and extending between said f drums, nipples arranged on each of said feed water pipes and pointing into the tubes of an associated group of downtake tubes. and means for serially `supplying feed water to the feed water supply pipes for projection through said nipples into the several groups of downtake tubes.

l1. In a water tube boiler, a plurality of steam and water drums. outer-water drums associated with said drums, a central water drum, connections between the outer and central water drums, at least one group of uptake tubes extending between the central water drum and each of the steam and waterdrums, a plurality of groups of downtake tubes extending between each of said steam and water drums and itsassociated outer water drum, a feed water supply pipe in the steam and water drums for each group of downtake tubes, nipples arranged'on each of said feed water vpipes and pointing into the tubes of an associated group of downtake tubes, a multiple plunger feed water pump, and connections between said pump and the several feed water supply pipes for supplying feed water to said pipes serially for projection through said nipples into the several groups of downtake tubes.

12. In a water tube boiler, a steam and water drum, a water drum, at least one bank of uptake tubes extending between said drums, a plurality oi banks of downtake tubes extending between said drums, means for injecting feed water serially into said groups of downtake tubes whereby to assist circulation of feed and boiler water in said boiler, and means disposed in said water drum to further assist the circulation as aforesaid.

13. In a water tube boiler, a steam and water drum, outer and central water connections between the outer and central water drums, at least one bank of uptake tubes extending between said central and said steam and water drums, a plurality of banks of downtake tubes extending between said steam and said outer drums, means for injecting feed water serially into the several banks of downtake tubes whereby to assist the circulation of feed and boiler water in the boiler, and means disposed in said water drum to further assist the circulation as aforesaid.

'14. In a water tube boiler, a plurality of steam and water drums, outer water drums associated with said drums, acentral water drum, connections between the outer and central water drums, at least one bank of uptake tubes extending betweeen the central water drum and each of the steam and water drums, a plurality of banks of downtake tubes extending between each of the steam and water drums and its associated outer water drum, means for injecting feed water serially into the several groups of downtake tubes wherebyto assist the circulation of feed and boiler water in said boiler, and means disposed in said water drum to further assist the circulation as aforesaid.

15. In a water tube boiler. a. seam and water drum, a water drum. at least one bank of uptake tubes extending between 'said drums, at least one bank of downtake tubes connected to said steam and water drum, a water connection between the lower ends of the downtake tubes and an end of said water drum, andmeans disposed in said water 4drum and extending substantially the length thereof, said means being operative to distribute the incoming water lengthwise of the drum and to set up a iiow of water from said downtake to said uptake tubes.

16. In a water tube boiler, a steam4 and water drum, a water header, a water drum, at least one bank of uptake tubes ex water and said steam and w ter drums, at least one bank of downtake tubes extending between 75 nding between said said steam and water drum and said header, a tubular impeller disposed in said water drum, said impeller having perforations therein, and connections between said header and said impeller whereby water from said downtake tubes is delivered to the interior of said impeller.

17. In a. water tube boiler, a steam and water drum, outer water drums associatedvwith said drum, a central water drum. end connections be tween said outer and said central water drums,

at least one bank of uptake tubes extending between said central and said steam and Water drums, at least one bank of downtake tubes extending between said steam and water and said outer water drums, and a perforated tubular impeller disposed in said central water drum and operative to receive water through said end connections from said outer water drums and to deliver same through said perforations to'said uptake tubes. v

18. In a water tube boiler, a steam and water drum, a water header, a water drum, at least one bank of uptake tubes extending between said drums, at least one group of downtake tubes extending between the steam and water drum and the header, impeller means disposed in the water drum comprising a tubular runner extending substantially the length of said water drum, and end connections between said header andl said runner adapted to deliver downcoming water to the interior of said runner, the runner having perforations through which the water passes into said water drum.

19. In a water tube boiler, a steam and water drum, a water header, a water drum, at least one bank of uptake tubes extending between said drums, at least one group oi downtake tubes extending between said steam and water drum and said header, impeller means diposed in the water drum comprising a tubular runner extending substantlally the length of said water drum, end connections between said header and said runner adapted to deliver downcoming water to the interior of said runner, the runner having perforations through which the water passes into said water drum, and impeller blades carried by said runner and operative to force water passing through said perforations into said upow tubes.

20. In a water tube boiler, a steam and water drum, a water drum, uptake tubes extending be tween said water drum and said steam and water 

